1. Field of the Invention
The present invention relates to a power-controlled bed, and more particularly to a power-controlled bed having an upper bed frame adapted to statically stay at a selected position or dynamically shift between two or more selected position combinations through manual or automatic control, so that the bed could be used in homes, hotels, recreation centers, hospitals and other health-care centers in the form of furniture or medical instrument. The present invention also relates to a method for controlling operations of the power-controlled bed.
2. Description of the Prior Art
There are many types of power-controlled beds known in the prior art. The following are some examples of these conventional power-controlled beds:    a. Taiwan New Utility Model Patent Application No. 87218307 laid open under Patent Publication No. 370869 entitled “A Power-controlled Bed” discloses a power-controlled bed for leisure purpose, a back-resting portion and a leg-resting portion of a mattress of the bed may be adjusted to different angles of elevation.    b. Taiwan New Utility Model Patent Application No. 86200788 laid open under Patent Publication No. 325689 entitled “An Automatic Sickbed” discloses a general sickbed including a mattress that has angle and height adjustable back-resting and leg-resting portions.    c. Taiwan New Utility Model Patent Application No. 82210483 laid open under Patent Publication No. 268281 entitled “A Bed for Rehabilitation” discloses a bed as an aid to rehabilitation. The bed is particularly designed for medical and rehabilitating purposes and could be adjusted to different angles of inclination.    d. Taiwan Invention Patent Application No. 87114125 laid open under Patent publication No. 372863 entitled “A Multi-functional Bed Structure and Method for Controlling Operations Thereof”, and a corresponding Chinese Invention Patent Invention Application No. 01131350.1 entitled “A Power-controlled Bed and Method for Controlling Operations Thereof”, both invented by the same inventor of the present invention.
All the above-mentioned leisure beds and sickbeds, which are either prior art or laid open, could not be adjusted to a considerably large angle of elevation, and could not be dynamically shifted between two or more position combinations. Furthermore, the conventional power-controlled beds for medical treatment and rehabilitation purposes, including those of the prior art and that disclosed in the inventor's Taiwan Patent Publication No. 372863, include complicate structures and are therefore too expensive to be widely accepted by most consumers.